1. Field of the Invention
The invention relates to a method for carbon nanotube emitter surface treatment, which is used to increase the number of CNTs (carbon nanotubes) exposed on a field emission display (FED) device for advancing the current density and magnitude of CNT emitters.
2. Description of the Prior Art
To implement a flat panel display, the CNT-FED (carbon nanotube field emission display) adopts the technology of screen-printing process and FED display in the prior art. It not only keeps the image quality of a CRT display, but also the advantage of power-saving and slim-volume, and with the characters of CNTs including low-conducting electronic field required, high density of emission current, and high stability. As a result, it may offer a flat panel display with good luminous efficiency, and large-size screen as well as power-saving and low-cost.
FIG. 1 shows the luminous theory of the triode structure of a carbon nanotube field emitter display (CNT-FED) in the prior art. The display includes an array structure, which is used to raise the electronic energy up, advance the luminous efficiency, and diminish the control voltage. The manufacturing of the display structure based on the CNT-FED luminous theory includes the processing steps of fabricating a cathode plate 102 above a substrate 101, and further depositing the nano-scale carbon nanotube on the cathode plate 102 to serve as an electronic source 103. The cathode plate 102 connects with a gate 105 by a dielectric 104, and a voltage generated from the gate 105 is used to pull the electronics out of the cathode plate 102. The current direction of the electronics from cathode plate 102 is in the directions of arrows shown on FIG. 1. Because of an anode plate 107 set on the triode structure, the electronics emit from cathode plate 102 and impact on fluorescent screen 106. Finally, the display generates the red, green and blue light through a glass plate 108.
In the prior art, when manufacturing the CNT emitters, the CNTs (Carbon Nano Tubes) and the organic matters are mixed to produce the CNT paste to be coated on the substrate and processed with masking by using the screen printing technology so as to form a field emission electronic source. Therefore, the number of the CNTs exposed on the surface of the CNT layer is closely related to the density of the field emission current. It is the key factor that affects the current density of the field emission display. However, the drawback of the prior art is in the problem associated with the uniformity of the field emission electronic source.
In order to resolve the problem of the uniformity of the surface of the CNT layer of the CNT emitters in the prior art, Samsung Electronic Inc. provides a technology where the laser scanning method is used for evening the surface. In U.S. Pat. No. 6,436,221, titled with “Method of Improving Field Emission Efficiency for Fabricating Carbon Nanotube Field Emitters”, a manufacturing process for improving the field emission efficiency of the CNT electronic source is provided.